• Phonetics and Speech Sciences
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• v.4 no.1
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• pp.13-20
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• 2012

A lax stop in Korean, one of the three laryngeal contrastive stops, has undergone a sound change in terms of its acoustic properties. Prior production studies described this recent lax stop as being differentiated from tense and aspirated stops primarily by fundamental frequencies (f0). And, the acoustic property of voice onset time (VOT) further separates tense stops from lax and aspirated stops. The current research explores how these two major acoustic parameters of f0 and VOT cue the three stop categories in Korean adult listeners' perception. Thirty-one native speakers of Korean participated in two experimental tasks: categorization judgment and within-category goodness ratings. Two sets of audio stimuli were prepared by synthesizing English and Korean male speakers' CV productions. The findings showed that while f0 cues listeners to lax stops as production patterns would predict, VOT were closely related to listeners' categorization and goodness ratings of lax stops. This suggests that accurate characterizations of the recent lax stop category need to be based on Korean speakers' perceptual behavior as well as production patterns.

• Proceedings of the KSPS conference
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• 1996.10a
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• pp.53-69
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• 1996

Much research has been done on the rues differentiating the three Korean stops in word initial position. This paper focuses on a more neglected area: the acoustic cues differentiating the medial tense and lax unaspirated stops. Eight adult Korean native speakers, four males and four females, pronounced sixteen minimal pairs containing the two series of medial stops with different preceding vowel qualities. The average duration of vowels before lax stops is 31 msec longer than before their tense counterparts (70 msec for lax vs 39 msec for tense). In addition, the average duration of the stop closure of tense stops is 135 msec longer than that of lax stops (69 msec for lax vs 204msec for tense). THESE DURATIONAL DIFFERENCES ARE 50 LARGE THAT THEY MAY BE PHONOLOGICALLY DETERMINED, NOT PHONETICALLY. Moreover, vowel duration varies with the speaker's sex. Female speakers have 5 msec shorter vowel duration before both stops. The quality of voicing, tense or lax, is also a cue to these two stop types, as it is in initial position, but the relative duration of the stops appears to be much more important cues. The duration of stops changes the stop perception while that of preceding vowel does not. The consequences of these results for the phonological description of Korean as well as the synthesis and automatic recognition of Korean will be discussed.

• Proceedings of the KSPS conference
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• 2006.05a
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• pp.55-58
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• 2006

The aim of this paper is to investigate the effects of postvocalic consonant cluster (Contrasting nasal-stops consonant with stops) on vowel duration. In particular we focused on the rate of vowel duration in their words. (Experimental I ) and the tendency of unreleased voiceless stops at the end of the words.(Experimental II). The result of experimental I showed that the rate of vowel duration which is preceding single voiceless stops are significantly longer than those preceding nasal-stops counterparts and the percentage of English native speakers was longer than those of Korean leaners of English Experiment II indicated that the tendency of unreleased stop consonants occurred more frequently on single voiceless stops than nasal-stop clusters and Korean learners of English were more frequently produced the unreleased stops than English natives.

• Speech Sciences
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• v.7 no.2
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• pp.139-155
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• 2000

The aim of this research is to investigate acoustic characteristics of three different types of Korean Stops-plain, tensed, and aspirated-, and employ these as a base to determine which one(s) can be used as perceptual cues. In this paper, we have examined acoustic characteristics of Korean Stops, especially voice onset time(VOT), closure duration(CD), degree of pitch of following vowels and differences in the intensity of the Stops build-up after the onset of voicing. From the above characteristics, differences can be made between word-initial and word-medial positions. That is to say, in word-initial position, the three Korean Stops are distinguished by VOT and pitch, whereas in word-medial by CD, VOT and pitch. However, the acoustic characteristics do not have the same value as perceptual cues. In both word-initial, and medial positions, the immediately following vowels play the most important role in perceiving Korean Stops. And in case of word'-medial positions,. CD and VOT also play important perceptual roles. In order to have a more fine-grained distinction among Korean Stops, we think future research should be done to investigate which factor(s) of the following vowels is/are the most determinative perceptual cue(s). However, based on our investigation, we may conclude that it is highly plausible that pitch can be one of the most important perceptual cues when distinguishing the three Korean Stops.

• Phonetics and Speech Sciences
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• v.7 no.3
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• pp.3-11
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• 2015

This study compared English and Korean speakers with regard to the nasalization of the English stops /b, d, g, p, t, k/before a nasal within and across a word boundary. Nine English and thirty Korean speakers participated in the experiment. We used 37 speech items with different grammatical structures. Overall the English informants rarely nasalized the stops while the Korean informants generally greatly nasalized them though widely varying from no nasalization to almost complete nasalization. In general, voiced stops were more likely to be nasalized than voiceless stops. Also, the alveolar stops /d, t/tended to be nasalized the most, the bilabial stops /b, p/ the second most, and the velar stops /g, k/ the least. Besides, the closer the grammatical relationship between neighboring words, the more likely the stop nasalization occurred. In contrast, the Korean syllabification - the addition of the vowel /i/ to the final stops - worked against the stop nasalization. On the other hand, different stress (accent) or rhythm effects of the two languages are assumed to contribute to the significantly different nasalization between English and Korean speakers. The spectrum of stop nasalization obtained from this study can be used as an index to measure how close a certain Korean speaker's stop nasalization is to English speakers'.

• Phonetics and Speech Sciences
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• v.2 no.3
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• pp.3-10
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• 2010

The proposal that a sound change is occurring in Korean stops was evidenced in this study through identification experiments on Korean stops. Perceptual weight of acoustic correlates to Korean stop manner contrast [VOT (Voice Onset Time), H1-H2 (amplitude difference between the first and second harmonics), and F0 (Fundamental frequency)] was examined with re-synthesized /$t^ha$/, /ta/, and /$t^*a$/ syllables for younger and older Seoul speakers of Korean. For the identification of the aspirated and lenis stops, F0 cue weight relative to VOT was greater for the younger listeners than the older listeners. For H1-H2 cue weight, the two listener groups were more or less the same. These findings were parallel to the production differences found in the earlier work of the author. Combined with production differences, these perception differences between younger and older generations of Seoul speakers suggested that there are generational differences in the phonetic targets of Korean aspirated and lenis stops and such differences are realized in the perception of the stops.

• Phonetics and Speech Sciences
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• v.1 no.3
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• pp.57-63
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• 2009

The two specific research questions pursued in this paper are: (i) how Korean speakers perceive Hindi stops in terms of the three laryngeal categories of Korean stops; (ii) how well Korean speakers do with an ABX perception test that utilizes a total of 52 Hindi minimal pairs where all sounds are identical except for the laryngeal features of a stop in each word. A total of 45 university students participated in this experiment. The results showed that (i) Koreans tended to perceive Hindi voiceless unaspirated stops as Korean fortis ones, voiceless aspirated stops as aspirated ones, voiced stops as lenis ones, and breathy stops as aspirated ones, and (ii) Koreans had difficulty in distinguishing between voiceless aspirated and breathy stops in Hindi.

• Phonetics and Speech Sciences
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• v.2 no.3
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• pp.29-36
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• 2010

The purposes of this study are (1) to see if language transfer effect is found in Korean speakers' pronunciation of English stops and to correct them and (2) to investigate the effectiveness of mimicry training and Speech Analyzer training on subjects' pronunciation of English stops. For these purposes, 20 Korean speakers' VOT values of English stops were measured using Speech Analyzer and their post-training production was compared with their pre-training production. The result shows that Korean speakers have no difficulty in correcting pronunciation errors of English voiceless stops and voiced stops and such a result indicates that language transfer effect is not noticed as expected. In addition, the result of pronunciation training shows that the training using Speech Analyzer is more effective than mimicry training.

• Phonetics and Speech Sciences
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• v.9 no.3
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• pp.41-47
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• 2017

The purpose of this study is to examine how speakers use VOT and f0 to distinguish tense, lax, and aspirated stops in isolated sentence reading and paragraph readings. To do so, a total of 20 males between the ages of 20-25 years old were asked to read (1) isolated sentences, (2) information-oriented text and (3) emotional expressive texts in which the stop pronunciation's VOT value and f0 were measured thereafter. The main results are as follows. In the isolate sentence reading, lax stops, and aspirated stops were distinguished by both VOT and f0, but for the Korean men that read reading texts, VOT is not a cue to distinguish between lax and aspirated stops. In general, the VOT differences between lax stops and aspirated stops were smaller for information-oriented texts and emotional expressive texts than that of the isolate sentence reading. In the paragraph reading that induces a natural utterance, the f0 dependence is greater for the distinction between lax and aspirated stops.

• Speech Sciences
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• v.2
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• pp.149-158
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• 1997

An Electropalatographic (EPG) study was made to investigate the articulatory distinction of three series of Korean stops according to tensity and the articulatory mechanism associated between tensity and coarticulatory effects. The results indicated that tensity of Korean stops is closely related to contact width and duration of complete closure, and that coarticulatory vocalic effects vary inversely with the degree of contact width and duration of complete closure.